The present invention relates generally to apparatus for recording and reproducing a video signal, and more particularly to apparatus for recording and reproducing a composite video signal on and from a rotary recording medium, such as a cylindrical or disc-like magnetic recording medium. More specifically, the invention relates to apparatus for recording/reproducing a composite video signal arranged to record and reproduce an odd field signal and an even field signal of a composite video signal, which is arranged that horizontal scanning and vertical scanning are performed in accordance with a scanning standard adopting an interlaced scanning whose interlacing ratio is 2 to 1, on a recording surface of a rotary recording medium (a disc-like or cylindrical recording medium) driven and rotated at a period equal to the vertical scanning period of the composite video signal such that the positions of horizontal sync signals in successive adjacent recording tracks are aligned with the recording positions of vertical sync signals in the direction of the width of the recording tracks.
As apparatus for recording and reproducing information signals are known various structures formed in accordance with various recording/reproducing systems using recording media of various forms. Among them apparatus for recording and reproducing information signals using a rotary recording medium arranged to record/reproduce information signals with a disc-like or cylindrical recording medium being rotated is simple in the structure of recording medium driving mechanism and record/reproduce transducer driving mechanism when compared with apparatus for recording and reproducing information signals using a tape-like or sheet-like recording medium. Furthermore, in recording/reproducing apparatus using a rotary recording medium as a recording medium, in the case that the rotary recording medium is of no-groove type or reproduction of inforamtion signals from the rotary recording medium is effected under a condition of noncontact with the rotary recording medium, random access is readily performed when reproducing information signals from the rotary recording medium while trick play by way of special reproduce modes, such as still picture reproduction, slow-motion reproduction, high-speed reproduction, is possible in the case that the information signal is a composite video signal. For these reasons apparatus for recording/reproducing information signals of various recording/reproducing systems (such as magnetic recording/repoducing system, photomagnetic recording/reproducing system, thermomagnetic recording/reproducing system, optical recording/reproducing system, reproducing system of electrostatic capacity variation detection type, mechanical reproducing system, and so on) using a rotary recording medium are widely practically used as is well known. The present applicant company is making a research for the practical use of recording/reproducing apparatus using a rotary recording medium of various record/reproduce system having the above-mentioned various features, and made many proposals relating to, for instance, micro magnetic recording/reproducing apparatus using a cylindrical magnetic recording medium as a micro recording/reproducing system.
Namely, microminiaturization of video tape recorders (VTRs) is recently planned while the microminiaturization of television cameras (television will be referred to as TV hereinafter) using solid imaging devices of various types and integrated circuits is also planned, and furthermore research and development are performed on a large scale on a microminiaturized VTR (so called electronic 8 mm device) integrated with a camera obtained by combining the above-mentioned microminiaturized camera with a microminiaturized VTR. In addition, research and development have been made on so called electronic cameras that record still pictures in place of still cameras using photographic films, and it was announced that an electronic camera of the type of recording a video signal using a micro flexible magnetic disc in place of a photographic film, which has been miniaturized to a degree of a single-lens reflex camera of 35 mm, has reached a stage of practical use.
The present applicant company also proposed, by way of Japanese patent applications No. 56-171868 (patent provisional publication No. 58-73072), No. 58-86946, and others, a micro image taking recording apparatus which is capable of recording in both frame-by-frame taking mode and continously recording mode for a short period of time using a cylindrical magnetic recording medium having a size of a cartridge of 35 mm photograph film. Corresponding applications of the above-mentioned Japanese application No. 56-171868 are U.S. application SN 436,418, British application No. 8230738 and West Germany application No. P32 39 659.7.
Since a relative linear velocity between a magnetic film of a cylindrical magnetic recording medium and a record/reproduce element is constant throughout the peripheral surface of the magnetic recording medium, there is a possibility that an entire peripheral surface can be effectively used as a region for recording and reproducing. In the case that the cylindrical magnetic recording medium has a size similar to a cartridge of 35 mm film (overall length: 47 mm, diameter: 25 mm) or a casing (overall length: 53 mm, diameter: 31 mm) for containing the above-mentioned cartridge, a relative linear velocity substantially equal to the relative linear velocity of 5.8 m/s between the magnetic head and the magnetic tape in a home use VTR of a type which is most popular in the world, is obtained, and therefore, when a cylindrical magnetic recording medium having a diameter of 31 mm and a length of 50 mm is rotated at 3600 rpm (the rotary recording medium is rotated at a rotation period equal to a vertical sync period of a composite video signal to be recorded on the rotary recording medium), and the periphery speed is set to 5.8 m/s for recording a portion corresponding to one field of a TV composite video signal per one revolution, where recording track width is 3 .mu. m, guard band width is 1.5 .mu.m, and the distance between tracks (track pitch) is 4.5 .mu.m, then a large recording capacity can be obtained with a small size such that stationary pictures of 10800 frames can be recorded on the cylindrical recording medium of the above-mentioned shape and size while it is possible to effect continuous recording of a normal composite video signal for three minutes or six minutes recording by adopting a field-skipping system. Furthermore, when a recording medium driving motor is provided at an internal space at the center of the magnetic recording medium, it is possible to miniaturize the magnetic recording/reproducing apparatus which is capable of magnetic recording or magnetic recording/reproducing, and this is advantageous when forming a small-sized and light-weighted image-taking recording apparatus.
When a composite video signal is recorded on a rotary recording medium with the rotary recording medium being rotated at a rotation period equal to the vertical scanning period of the composite video signal as described taking an exampe of the above-mentioned apparatus for recording/reproducing a composte video signal using a cylindrical magnetic recording medium as a rotary recording medium, a portion of one field of the composite video signal is recorded per one revolution of the rotary recording medium thereon. Therefore, when recording the composite video signal on the rotary recording medium under a condition that a recording element is continuously shifted by one recording track pitch per one revolution of the rotary recording medium, then spiral recording tracks are continuously formed on the rotary recording medium. On the other hand, when recording the composite video signal on the rotary recording medium under a condition that the recording element is stationary and the shifting of the recording element by one recording track pitch is of intermittent moving such that it is instantanously effected during vertical blanking signal period, then annular recording tracks are formed on the rotary recording medium.
In order to stably rotating the above-mentioned rotary recording medium at a predetermined rotational period and rotational phase, a rotation control system has hitherto been used so that the rotational period and the rotational phase of a driving motor of the rotary recording medium are controlled using a phase error signal obtained by phase comparison between an output of a sensor which is capable of detecting the rotational period and the rotational phase of the rotary recording medium and a vertical sync signal of the composite video signal which is an objective of recording by the rotary recording medium.
As will be described in detail with reference to accompanying drawings, conventional appartus for recording/reproducing a composite video signal on a rotary recording medium have suffered from various problems, such as the deterioration of picture quality due to crosstalk from adjacent recording tracks, difficulty in automatic tracking, difficulty in the operation of the servo system in a VTR when dubbing is intended, difficulty in frame-by-frame taking and recording and so on.